src/cc/trees/layer_tree_impl.cc

   1 // Copyright 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "cc/trees/layer_tree_impl.h"
   6
   7 #include <limits>
   8 #include <set>
   9
  10 #include "base/debug/trace_event.h"
  11 #include "base/debug/trace_event_argument.h"
  12 #include "cc/animation/keyframed_animation_curve.h"
  13 #include "cc/animation/scrollbar_animation_controller.h"
  14 #include "cc/animation/scrollbar_animation_controller_linear_fade.h"
  15 #include "cc/animation/scrollbar_animation_controller_thinning.h"
  16 #include "cc/base/math_util.h"
  17 #include "cc/base/util.h"
  18 #include "cc/debug/devtools_instrumentation.h"
  19 #include "cc/debug/traced_value.h"
  20 #include "cc/layers/heads_up_display_layer_impl.h"
  21 #include "cc/layers/layer.h"
  22 #include "cc/layers/layer_iterator.h"
  23 #include "cc/layers/render_surface_impl.h"
  24 #include "cc/layers/scrollbar_layer_impl_base.h"
  25 #include "cc/resources/ui_resource_request.h"
  26 #include "cc/trees/layer_tree_host_common.h"
  27 #include "cc/trees/layer_tree_host_impl.h"
  28 #include "cc/trees/occlusion_tracker.h"
  29 #include "ui/gfx/point_conversions.h"
  30 #include "ui/gfx/size_conversions.h"
  31 #include "ui/gfx/vector2d_conversions.h"
  32
  33 namespace cc {
  34
  35 // This class exists to split the LayerScrollOffsetDelegate between the
  36 // InnerViewportScrollLayer and the OuterViewportScrollLayer in a manner
  37 // that never requires the embedder or LayerImpl to know about.
  38 class LayerScrollOffsetDelegateProxy : public LayerImpl::ScrollOffsetDelegate {
  39  public:
  40   LayerScrollOffsetDelegateProxy(LayerImpl* layer,
  41                                  LayerScrollOffsetDelegate* delegate,
  42                                  LayerTreeImpl* layer_tree)
  43       : layer_(layer), delegate_(delegate), layer_tree_impl_(layer_tree) {}
  44   virtual ~LayerScrollOffsetDelegateProxy() {}
  45
  46   gfx::Vector2dF last_set_scroll_offset() const {
  47     return last_set_scroll_offset_;
  48   }
  49
  50   // LayerScrollOffsetDelegate implementation.
  51   virtual void SetTotalScrollOffset(const gfx::Vector2dF& new_offset) OVERRIDE {
  52     last_set_scroll_offset_ = new_offset;
  53     layer_tree_impl_->UpdateScrollOffsetDelegate();
  54   }
  55
  56   virtual gfx::Vector2dF GetTotalScrollOffset() OVERRIDE {
  57     return layer_tree_impl_->GetDelegatedScrollOffset(layer_);
  58   }
  59
  60   virtual bool IsExternalFlingActive() const OVERRIDE {
  61     return delegate_->IsExternalFlingActive();
  62   }
  63
  64  private:
  65   LayerImpl* layer_;
  66   LayerScrollOffsetDelegate* delegate_;
  67   LayerTreeImpl* layer_tree_impl_;
  68   gfx::Vector2dF last_set_scroll_offset_;
  69 };
  70
  71 LayerTreeImpl::LayerTreeImpl(LayerTreeHostImpl* layer_tree_host_impl)
  72     : layer_tree_host_impl_(layer_tree_host_impl),
  73       source_frame_number_(-1),
  74       hud_layer_(0),
  75       currently_scrolling_layer_(NULL),
  76       root_layer_scroll_offset_delegate_(NULL),
  77       background_color_(0),
  78       has_transparent_background_(false),
  79       page_scale_layer_(NULL),
  80       inner_viewport_scroll_layer_(NULL),
  81       outer_viewport_scroll_layer_(NULL),
  82       page_scale_factor_(1),
  83       page_scale_delta_(1),
  84       sent_page_scale_delta_(1),
  85       min_page_scale_factor_(0),
  86       max_page_scale_factor_(0),
  87       scrolling_layer_id_from_previous_tree_(0),
  88       contents_textures_purged_(false),
  89       requires_high_res_to_draw_(false),
  90       viewport_size_invalid_(false),
  91       needs_update_draw_properties_(true),
  92       needs_full_tree_sync_(true),
  93       next_activation_forces_redraw_(false),
  94       has_ever_been_drawn_(false),
  95       render_surface_layer_list_id_(0) {
  96 }
  97
  98 LayerTreeImpl::~LayerTreeImpl() {
  99   BreakSwapPromises(SwapPromise::SWAP_FAILS);
 100
 101   // Need to explicitly clear the tree prior to destroying this so that
 102   // the LayerTreeImpl pointer is still valid in the LayerImpl dtor.
 103   DCHECK(!root_layer_);
 104   DCHECK(layers_with_copy_output_request_.empty());
 105 }
 106
 107 void LayerTreeImpl::Shutdown() { root_layer_.reset(); }
 108
 109 void LayerTreeImpl::ReleaseResources() {
 110   if (root_layer_)
 111     ReleaseResourcesRecursive(root_layer_.get());
 112 }
 113
 114 void LayerTreeImpl::SetRootLayer(scoped_ptr<LayerImpl> layer) {
 115   if (inner_viewport_scroll_layer_)
 116     inner_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
 117   if (outer_viewport_scroll_layer_)
 118     outer_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
 119   inner_viewport_scroll_delegate_proxy_.reset();
 120   outer_viewport_scroll_delegate_proxy_.reset();
 121
 122   root_layer_ = layer.Pass();
 123   currently_scrolling_layer_ = NULL;
 124   inner_viewport_scroll_layer_ = NULL;
 125   outer_viewport_scroll_layer_ = NULL;
 126   page_scale_layer_ = NULL;
 127
 128   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 129 }
 130
 131 LayerImpl* LayerTreeImpl::InnerViewportScrollLayer() const {
 132   return inner_viewport_scroll_layer_;
 133 }
 134
 135 LayerImpl* LayerTreeImpl::OuterViewportScrollLayer() const {
 136   return outer_viewport_scroll_layer_;
 137 }
 138
 139 gfx::Vector2dF LayerTreeImpl::TotalScrollOffset() const {
 140   gfx::Vector2dF offset;
 141
 142   if (inner_viewport_scroll_layer_)
 143     offset += inner_viewport_scroll_layer_->TotalScrollOffset();
 144
 145   if (outer_viewport_scroll_layer_)
 146     offset += outer_viewport_scroll_layer_->TotalScrollOffset();
 147
 148   return offset;
 149 }
 150
 151 gfx::Vector2dF LayerTreeImpl::TotalMaxScrollOffset() const {
 152   gfx::Vector2dF offset;
 153
 154   if (inner_viewport_scroll_layer_)
 155     offset += inner_viewport_scroll_layer_->MaxScrollOffset();
 156
 157   if (outer_viewport_scroll_layer_)
 158     offset += outer_viewport_scroll_layer_->MaxScrollOffset();
 159
 160   return offset;
 161 }
 162 gfx::Vector2dF LayerTreeImpl::TotalScrollDelta() const {
 163   DCHECK(inner_viewport_scroll_layer_);
 164   gfx::Vector2dF delta = inner_viewport_scroll_layer_->ScrollDelta();
 165
 166   if (outer_viewport_scroll_layer_)
 167     delta += outer_viewport_scroll_layer_->ScrollDelta();
 168
 169   return delta;
 170 }
 171
 172 scoped_ptr<LayerImpl> LayerTreeImpl::DetachLayerTree() {
 173   // Clear all data structures that have direct references to the layer tree.
 174   scrolling_layer_id_from_previous_tree_ =
 175     currently_scrolling_layer_ ? currently_scrolling_layer_->id() : 0;
 176   if (inner_viewport_scroll_layer_)
 177     inner_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
 178   if (outer_viewport_scroll_layer_)
 179     outer_viewport_scroll_layer_->SetScrollOffsetDelegate(NULL);
 180   inner_viewport_scroll_delegate_proxy_.reset();
 181   outer_viewport_scroll_delegate_proxy_.reset();
 182   inner_viewport_scroll_layer_ = NULL;
 183   outer_viewport_scroll_layer_ = NULL;
 184   page_scale_layer_ = NULL;
 185   currently_scrolling_layer_ = NULL;
 186
 187   render_surface_layer_list_.clear();
 188   set_needs_update_draw_properties();
 189   return root_layer_.Pass();
 190 }
 191
 192 void LayerTreeImpl::PushPropertiesTo(LayerTreeImpl* target_tree) {
 193   // The request queue should have been processed and does not require a push.
 194   DCHECK_EQ(ui_resource_request_queue_.size(), 0u);
 195
 196   if (next_activation_forces_redraw_) {
 197     target_tree->ForceRedrawNextActivation();
 198     next_activation_forces_redraw_ = false;
 199   }
 200
 201   target_tree->PassSwapPromises(&swap_promise_list_);
 202
 203   target_tree->SetPageScaleValues(
 204       page_scale_factor(), min_page_scale_factor(), max_page_scale_factor(),
 205       target_tree->page_scale_delta() / target_tree->sent_page_scale_delta());
 206   target_tree->set_sent_page_scale_delta(1);
 207
 208   if (page_scale_layer_ && inner_viewport_scroll_layer_) {
 209     target_tree->SetViewportLayersFromIds(
 210         page_scale_layer_->id(),
 211         inner_viewport_scroll_layer_->id(),
 212         outer_viewport_scroll_layer_ ? outer_viewport_scroll_layer_->id()
 213                                      : Layer::INVALID_ID);
 214   } else {
 215     target_tree->ClearViewportLayers();
 216   }
 217
 218   target_tree->RegisterSelection(selection_start_, selection_end_);
 219
 220   // This should match the property synchronization in
 221   // LayerTreeHost::finishCommitOnImplThread().
 222   target_tree->set_source_frame_number(source_frame_number());
 223   target_tree->set_background_color(background_color());
 224   target_tree->set_has_transparent_background(has_transparent_background());
 225
 226   if (ContentsTexturesPurged())
 227     target_tree->SetContentsTexturesPurged();
 228   else
 229     target_tree->ResetContentsTexturesPurged();
 230
 231   if (ViewportSizeInvalid())
 232     target_tree->SetViewportSizeInvalid();
 233   else
 234     target_tree->ResetViewportSizeInvalid();
 235
 236   if (hud_layer())
 237     target_tree->set_hud_layer(static_cast<HeadsUpDisplayLayerImpl*>(
 238         LayerTreeHostCommon::FindLayerInSubtree(
 239             target_tree->root_layer(), hud_layer()->id())));
 240   else
 241     target_tree->set_hud_layer(NULL);
 242
 243   target_tree->has_ever_been_drawn_ = false;
 244 }
 245
 246 LayerImpl* LayerTreeImpl::InnerViewportContainerLayer() const {
 247   return inner_viewport_scroll_layer_
 248              ? inner_viewport_scroll_layer_->scroll_clip_layer()
 249              : NULL;
 250 }
 251
 252 LayerImpl* LayerTreeImpl::CurrentlyScrollingLayer() const {
 253   DCHECK(IsActiveTree());
 254   return currently_scrolling_layer_;
 255 }
 256
 257 void LayerTreeImpl::SetCurrentlyScrollingLayer(LayerImpl* layer) {
 258   if (currently_scrolling_layer_ == layer)
 259     return;
 260
 261   if (currently_scrolling_layer_ &&
 262       currently_scrolling_layer_->scrollbar_animation_controller())
 263     currently_scrolling_layer_->scrollbar_animation_controller()
 264         ->DidScrollEnd();
 265   currently_scrolling_layer_ = layer;
 266   if (layer && layer->scrollbar_animation_controller())
 267     layer->scrollbar_animation_controller()->DidScrollBegin();
 268 }
 269
 270 void LayerTreeImpl::ClearCurrentlyScrollingLayer() {
 271   SetCurrentlyScrollingLayer(NULL);
 272   scrolling_layer_id_from_previous_tree_ = 0;
 273 }
 274
 275 float LayerTreeImpl::VerticalAdjust(const int clip_layer_id) const {
 276   LayerImpl* container_layer = InnerViewportContainerLayer();
 277   if (!container_layer || clip_layer_id != container_layer->id())
 278     return 0.f;
 279
 280   return layer_tree_host_impl_->VerticalAdjust();
 281 }
 282
 283 namespace {
 284
 285 void ForceScrollbarParameterUpdateAfterScaleChange(LayerImpl* current_layer) {
 286   if (!current_layer)
 287     return;
 288
 289   while (current_layer) {
 290     current_layer->ScrollbarParametersDidChange();
 291     current_layer = current_layer->parent();
 292   }
 293 }
 294
 295 }  // namespace
 296
 297 void LayerTreeImpl::SetPageScaleFactorAndLimits(float page_scale_factor,
 298     float min_page_scale_factor, float max_page_scale_factor) {
 299   SetPageScaleValues(page_scale_factor, min_page_scale_factor,
 300       max_page_scale_factor, page_scale_delta_);
 301 }
 302
 303 void LayerTreeImpl::SetPageScaleDelta(float delta) {
 304   SetPageScaleValues(page_scale_factor_, min_page_scale_factor_,
 305       max_page_scale_factor_, delta);
 306 }
 307
 308 void LayerTreeImpl::SetPageScaleValues(float page_scale_factor,
 309       float min_page_scale_factor, float max_page_scale_factor,
 310       float page_scale_delta) {
 311   bool page_scale_changed =
 312       min_page_scale_factor != min_page_scale_factor_ ||
 313       max_page_scale_factor != max_page_scale_factor_ ||
 314       page_scale_factor != page_scale_factor_;
 315
 316   min_page_scale_factor_ = min_page_scale_factor;
 317   max_page_scale_factor_ = max_page_scale_factor;
 318   page_scale_factor_ = page_scale_factor;
 319
 320   float total = page_scale_factor_ * page_scale_delta;
 321   if (min_page_scale_factor_ && total < min_page_scale_factor_)
 322     page_scale_delta = min_page_scale_factor_ / page_scale_factor_;
 323   else if (max_page_scale_factor_ && total > max_page_scale_factor_)
 324     page_scale_delta = max_page_scale_factor_ / page_scale_factor_;
 325
 326   if (page_scale_delta_ == page_scale_delta && !page_scale_changed)
 327     return;
 328
 329   if (page_scale_delta_ != page_scale_delta) {
 330     page_scale_delta_ = page_scale_delta;
 331
 332     if (IsActiveTree()) {
 333       LayerTreeImpl* pending_tree = layer_tree_host_impl_->pending_tree();
 334       if (pending_tree) {
 335         DCHECK_EQ(1, pending_tree->sent_page_scale_delta());
 336         pending_tree->SetPageScaleDelta(
 337             page_scale_delta_ / sent_page_scale_delta_);
 338       }
 339     }
 340
 341     set_needs_update_draw_properties();
 342   }
 343
 344   if (root_layer_scroll_offset_delegate_) {
 345     root_layer_scroll_offset_delegate_->UpdateRootLayerState(
 346         TotalScrollOffset(),
 347         TotalMaxScrollOffset(),
 348         ScrollableSize(),
 349         total_page_scale_factor(),
 350         min_page_scale_factor_,
 351         max_page_scale_factor_);
 352   }
 353
 354   ForceScrollbarParameterUpdateAfterScaleChange(page_scale_layer());
 355 }
 356
 357 gfx::SizeF LayerTreeImpl::ScrollableViewportSize() const {
 358   if (outer_viewport_scroll_layer_)
 359     return layer_tree_host_impl_->UnscaledScrollableViewportSize();
 360   else
 361     return gfx::ScaleSize(
 362         layer_tree_host_impl_->UnscaledScrollableViewportSize(),
 363         1.0f / total_page_scale_factor());
 364 }
 365
 366 gfx::Rect LayerTreeImpl::RootScrollLayerDeviceViewportBounds() const {
 367   LayerImpl* root_scroll_layer = OuterViewportScrollLayer()
 368                                      ? OuterViewportScrollLayer()
 369                                      : InnerViewportScrollLayer();
 370   if (!root_scroll_layer || root_scroll_layer->children().empty())
 371     return gfx::Rect();
 372   LayerImpl* layer = root_scroll_layer->children()[0];
 373   return MathUtil::MapEnclosingClippedRect(layer->screen_space_transform(),
 374                                            gfx::Rect(layer->content_bounds()));
 375 }
 376
 377 static void ApplySentScrollDeltasFromAbortedCommitTo(LayerImpl* layer) {
 378   layer->ApplySentScrollDeltasFromAbortedCommit();
 379 }
 380
 381 void LayerTreeImpl::ApplySentScrollAndScaleDeltasFromAbortedCommit() {
 382   DCHECK(IsActiveTree());
 383
 384   page_scale_factor_ *= sent_page_scale_delta_;
 385   page_scale_delta_ /= sent_page_scale_delta_;
 386   sent_page_scale_delta_ = 1.f;
 387
 388   if (!root_layer())
 389     return;
 390
 391   LayerTreeHostCommon::CallFunctionForSubtree(
 392       root_layer(), base::Bind(&ApplySentScrollDeltasFromAbortedCommitTo));
 393 }
 394
 395 static void ApplyScrollDeltasSinceBeginMainFrameTo(LayerImpl* layer) {
 396   layer->ApplyScrollDeltasSinceBeginMainFrame();
 397 }
 398
 399 void LayerTreeImpl::ApplyScrollDeltasSinceBeginMainFrame() {
 400   DCHECK(IsPendingTree());
 401   if (!root_layer())
 402     return;
 403
 404   LayerTreeHostCommon::CallFunctionForSubtree(
 405       root_layer(), base::Bind(&ApplyScrollDeltasSinceBeginMainFrameTo));
 406 }
 407
 408 void LayerTreeImpl::SetViewportLayersFromIds(
 409     int page_scale_layer_id,
 410     int inner_viewport_scroll_layer_id,
 411     int outer_viewport_scroll_layer_id) {
 412   page_scale_layer_ = LayerById(page_scale_layer_id);
 413   DCHECK(page_scale_layer_);
 414
 415   inner_viewport_scroll_layer_ =
 416       LayerById(inner_viewport_scroll_layer_id);
 417   DCHECK(inner_viewport_scroll_layer_);
 418
 419   outer_viewport_scroll_layer_ =
 420       LayerById(outer_viewport_scroll_layer_id);
 421   DCHECK(outer_viewport_scroll_layer_ ||
 422          outer_viewport_scroll_layer_id == Layer::INVALID_ID);
 423
 424   if (!root_layer_scroll_offset_delegate_)
 425     return;
 426
 427   inner_viewport_scroll_delegate_proxy_ = make_scoped_ptr(
 428       new LayerScrollOffsetDelegateProxy(inner_viewport_scroll_layer_,
 429                                          root_layer_scroll_offset_delegate_,
 430                                          this));
 431
 432   if (outer_viewport_scroll_layer_)
 433     outer_viewport_scroll_delegate_proxy_ = make_scoped_ptr(
 434         new LayerScrollOffsetDelegateProxy(outer_viewport_scroll_layer_,
 435                                            root_layer_scroll_offset_delegate_,
 436                                            this));
 437 }
 438
 439 void LayerTreeImpl::ClearViewportLayers() {
 440   page_scale_layer_ = NULL;
 441   inner_viewport_scroll_layer_ = NULL;
 442   outer_viewport_scroll_layer_ = NULL;
 443 }
 444
 445 bool LayerTreeImpl::UpdateDrawProperties() {
 446   if (!needs_update_draw_properties_)
 447     return true;
 448
 449   // For max_texture_size.
 450   if (!layer_tree_host_impl_->renderer())
 451     return false;
 452
 453   if (!root_layer())
 454     return false;
 455
 456   needs_update_draw_properties_ = false;
 457   render_surface_layer_list_.clear();
 458
 459   {
 460     TRACE_EVENT2("cc",
 461                  "LayerTreeImpl::UpdateDrawProperties",
 462                  "IsActive",
 463                  IsActiveTree(),
 464                  "SourceFrameNumber",
 465                  source_frame_number_);
 466     LayerImpl* page_scale_layer =
 467         page_scale_layer_ ? page_scale_layer_ : InnerViewportContainerLayer();
 468     bool can_render_to_separate_surface = !resourceless_software_draw();
 469
 470     ++render_surface_layer_list_id_;
 471     LayerTreeHostCommon::CalcDrawPropsImplInputs inputs(
 472         root_layer(),
 473         DrawViewportSize(),
 474         layer_tree_host_impl_->DrawTransform(),
 475         device_scale_factor(),
 476         total_page_scale_factor(),
 477         page_scale_layer,
 478         MaxTextureSize(),
 479         settings().can_use_lcd_text,
 480         can_render_to_separate_surface,
 481         settings().layer_transforms_should_scale_layer_contents,
 482         &render_surface_layer_list_,
 483         render_surface_layer_list_id_);
 484     LayerTreeHostCommon::CalculateDrawProperties(&inputs);
 485   }
 486
 487   {
 488     TRACE_EVENT2("cc",
 489                  "LayerTreeImpl::UpdateTilePriorities",
 490                  "IsActive",
 491                  IsActiveTree(),
 492                  "SourceFrameNumber",
 493                  source_frame_number_);
 494     scoped_ptr<OcclusionTracker<LayerImpl> > occlusion_tracker;
 495     if (settings().use_occlusion_for_tile_prioritization) {
 496       occlusion_tracker.reset(new OcclusionTracker<LayerImpl>(
 497           root_layer()->render_surface()->content_rect()));
 498       occlusion_tracker->set_minimum_tracking_size(
 499           settings().minimum_occlusion_tracking_size);
 500     }
 501
 502     // LayerIterator is used here instead of CallFunctionForSubtree to only
 503     // UpdateTilePriorities on layers that will be visible (and thus have valid
 504     // draw properties) and not because any ordering is required.
 505     typedef LayerIterator<LayerImpl> LayerIteratorType;
 506     LayerIteratorType end = LayerIteratorType::End(&render_surface_layer_list_);
 507     for (LayerIteratorType it =
 508              LayerIteratorType::Begin(&render_surface_layer_list_);
 509          it != end;
 510          ++it) {
 511       if (occlusion_tracker)
 512         occlusion_tracker->EnterLayer(it);
 513
 514       LayerImpl* layer = *it;
 515       if (it.represents_itself())
 516         layer->UpdateTiles(occlusion_tracker.get());
 517
 518       if (!it.represents_contributing_render_surface()) {
 519         if (occlusion_tracker)
 520           occlusion_tracker->LeaveLayer(it);
 521         continue;
 522       }
 523
 524       if (layer->mask_layer())
 525         layer->mask_layer()->UpdateTiles(occlusion_tracker.get());
 526       if (layer->replica_layer() && layer->replica_layer()->mask_layer())
 527         layer->replica_layer()->mask_layer()->UpdateTiles(
 528             occlusion_tracker.get());
 529
 530       if (occlusion_tracker)
 531         occlusion_tracker->LeaveLayer(it);
 532     }
 533   }
 534
 535   DCHECK(!needs_update_draw_properties_) <<
 536       "CalcDrawProperties should not set_needs_update_draw_properties()";
 537   return true;
 538 }
 539
 540 const LayerImplList& LayerTreeImpl::RenderSurfaceLayerList() const {
 541   // If this assert triggers, then the list is dirty.
 542   DCHECK(!needs_update_draw_properties_);
 543   return render_surface_layer_list_;
 544 }
 545
 546 gfx::Size LayerTreeImpl::ScrollableSize() const {
 547   LayerImpl* root_scroll_layer = OuterViewportScrollLayer()
 548                                      ? OuterViewportScrollLayer()
 549                                      : InnerViewportScrollLayer();
 550   if (!root_scroll_layer || root_scroll_layer->children().empty())
 551     return gfx::Size();
 552   return root_scroll_layer->children()[0]->bounds();
 553 }
 554
 555 LayerImpl* LayerTreeImpl::LayerById(int id) {
 556   LayerIdMap::iterator iter = layer_id_map_.find(id);
 557   return iter != layer_id_map_.end() ? iter->second : NULL;
 558 }
 559
 560 void LayerTreeImpl::RegisterLayer(LayerImpl* layer) {
 561   DCHECK(!LayerById(layer->id()));
 562   layer_id_map_[layer->id()] = layer;
 563 }
 564
 565 void LayerTreeImpl::UnregisterLayer(LayerImpl* layer) {
 566   DCHECK(LayerById(layer->id()));
 567   layer_id_map_.erase(layer->id());
 568 }
 569
 570 size_t LayerTreeImpl::NumLayers() {
 571   return layer_id_map_.size();
 572 }
 573
 574 void LayerTreeImpl::PushPersistedState(LayerTreeImpl* pending_tree) {
 575   pending_tree->SetCurrentlyScrollingLayer(
 576       LayerTreeHostCommon::FindLayerInSubtree(pending_tree->root_layer(),
 577           currently_scrolling_layer_ ? currently_scrolling_layer_->id() : 0));
 578 }
 579
 580 static void DidBecomeActiveRecursive(LayerImpl* layer) {
 581   layer->DidBecomeActive();
 582   if (layer->mask_layer())
 583     layer->mask_layer()->DidBecomeActive();
 584   if (layer->replica_layer() && layer->replica_layer()->mask_layer())
 585     layer->replica_layer()->mask_layer()->DidBecomeActive();
 586
 587   for (size_t i = 0; i < layer->children().size(); ++i)
 588     DidBecomeActiveRecursive(layer->children()[i]);
 589 }
 590
 591 void LayerTreeImpl::DidBecomeActive() {
 592   if (next_activation_forces_redraw_) {
 593     layer_tree_host_impl_->SetFullRootLayerDamage();
 594     next_activation_forces_redraw_ = false;
 595   }
 596
 597   if (scrolling_layer_id_from_previous_tree_) {
 598     currently_scrolling_layer_ = LayerTreeHostCommon::FindLayerInSubtree(
 599         root_layer(), scrolling_layer_id_from_previous_tree_);
 600   }
 601
 602   // Always reset this flag on activation, as we would only have activated
 603   // if we were in a good state.
 604   ResetRequiresHighResToDraw();
 605
 606   if (root_layer())
 607     DidBecomeActiveRecursive(root_layer());
 608
 609   devtools_instrumentation::DidActivateLayerTree(layer_tree_host_impl_->id(),
 610                                                  source_frame_number_);
 611 }
 612
 613 bool LayerTreeImpl::ContentsTexturesPurged() const {
 614   return contents_textures_purged_;
 615 }
 616
 617 void LayerTreeImpl::SetContentsTexturesPurged() {
 618   if (contents_textures_purged_)
 619     return;
 620   contents_textures_purged_ = true;
 621   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 622 }
 623
 624 void LayerTreeImpl::ResetContentsTexturesPurged() {
 625   if (!contents_textures_purged_)
 626     return;
 627   contents_textures_purged_ = false;
 628   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 629 }
 630
 631 void LayerTreeImpl::SetRequiresHighResToDraw() {
 632   requires_high_res_to_draw_ = true;
 633 }
 634
 635 void LayerTreeImpl::ResetRequiresHighResToDraw() {
 636   requires_high_res_to_draw_ = false;
 637 }
 638
 639 bool LayerTreeImpl::RequiresHighResToDraw() const {
 640   return requires_high_res_to_draw_;
 641 }
 642
 643 bool LayerTreeImpl::ViewportSizeInvalid() const {
 644   return viewport_size_invalid_;
 645 }
 646
 647 void LayerTreeImpl::SetViewportSizeInvalid() {
 648   viewport_size_invalid_ = true;
 649   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 650 }
 651
 652 void LayerTreeImpl::ResetViewportSizeInvalid() {
 653   viewport_size_invalid_ = false;
 654   layer_tree_host_impl_->OnCanDrawStateChangedForTree();
 655 }
 656
 657 Proxy* LayerTreeImpl::proxy() const {
 658   return layer_tree_host_impl_->proxy();
 659 }
 660
 661 const LayerTreeSettings& LayerTreeImpl::settings() const {
 662   return layer_tree_host_impl_->settings();
 663 }
 664
 665 const RendererCapabilitiesImpl& LayerTreeImpl::GetRendererCapabilities() const {
 666   return layer_tree_host_impl_->GetRendererCapabilities();
 667 }
 668
 669 ContextProvider* LayerTreeImpl::context_provider() const {
 670   return output_surface()->context_provider();
 671 }
 672
 673 OutputSurface* LayerTreeImpl::output_surface() const {
 674   return layer_tree_host_impl_->output_surface();
 675 }
 676
 677 ResourceProvider* LayerTreeImpl::resource_provider() const {
 678   return layer_tree_host_impl_->resource_provider();
 679 }
 680
 681 TileManager* LayerTreeImpl::tile_manager() const {
 682   return layer_tree_host_impl_->tile_manager();
 683 }
 684
 685 FrameRateCounter* LayerTreeImpl::frame_rate_counter() const {
 686   return layer_tree_host_impl_->fps_counter();
 687 }
 688
 689 PaintTimeCounter* LayerTreeImpl::paint_time_counter() const {
 690   return layer_tree_host_impl_->paint_time_counter();
 691 }
 692
 693 MemoryHistory* LayerTreeImpl::memory_history() const {
 694   return layer_tree_host_impl_->memory_history();
 695 }
 696
 697 bool LayerTreeImpl::resourceless_software_draw() const {
 698   return layer_tree_host_impl_->GetDrawMode() ==
 699          DRAW_MODE_RESOURCELESS_SOFTWARE;
 700 }
 701
 702 gfx::Size LayerTreeImpl::device_viewport_size() const {
 703   return layer_tree_host_impl_->device_viewport_size();
 704 }
 705
 706 bool LayerTreeImpl::IsActiveTree() const {
 707   return layer_tree_host_impl_->active_tree() == this;
 708 }
 709
 710 bool LayerTreeImpl::IsPendingTree() const {
 711   return layer_tree_host_impl_->pending_tree() == this;
 712 }
 713
 714 bool LayerTreeImpl::IsRecycleTree() const {
 715   return layer_tree_host_impl_->recycle_tree() == this;
 716 }
 717
 718 LayerImpl* LayerTreeImpl::FindActiveTreeLayerById(int id) {
 719   LayerTreeImpl* tree = layer_tree_host_impl_->active_tree();
 720   if (!tree)
 721     return NULL;
 722   return tree->LayerById(id);
 723 }
 724
 725 LayerImpl* LayerTreeImpl::FindPendingTreeLayerById(int id) {
 726   LayerTreeImpl* tree = layer_tree_host_impl_->pending_tree();
 727   if (!tree)
 728     return NULL;
 729   return tree->LayerById(id);
 730 }
 731
 732 LayerImpl* LayerTreeImpl::FindRecycleTreeLayerById(int id) {
 733   LayerTreeImpl* tree = layer_tree_host_impl_->recycle_tree();
 734   if (!tree)
 735     return NULL;
 736   return tree->LayerById(id);
 737 }
 738
 739 int LayerTreeImpl::MaxTextureSize() const {
 740   return layer_tree_host_impl_->GetRendererCapabilities().max_texture_size;
 741 }
 742
 743 bool LayerTreeImpl::PinchGestureActive() const {
 744   return layer_tree_host_impl_->pinch_gesture_active();
 745 }
 746
 747 base::TimeTicks LayerTreeImpl::CurrentFrameTimeTicks() const {
 748   return layer_tree_host_impl_->CurrentFrameTimeTicks();
 749 }
 750
 751 base::TimeDelta LayerTreeImpl::begin_impl_frame_interval() const {
 752   return layer_tree_host_impl_->begin_impl_frame_interval();
 753 }
 754
 755 void LayerTreeImpl::SetNeedsCommit() {
 756   layer_tree_host_impl_->SetNeedsCommit();
 757 }
 758
 759 gfx::Rect LayerTreeImpl::DeviceViewport() const {
 760   return layer_tree_host_impl_->DeviceViewport();
 761 }
 762
 763 gfx::Size LayerTreeImpl::DrawViewportSize() const {
 764   return layer_tree_host_impl_->DrawViewportSize();
 765 }
 766
 767 const gfx::Rect LayerTreeImpl::ViewportRectForTilePriority() const {
 768   return layer_tree_host_impl_->ViewportRectForTilePriority();
 769 }
 770
 771 scoped_ptr<ScrollbarAnimationController>
 772 LayerTreeImpl::CreateScrollbarAnimationController(LayerImpl* scrolling_layer) {
 773   DCHECK(settings().scrollbar_fade_delay_ms);
 774   DCHECK(settings().scrollbar_fade_duration_ms);
 775   base::TimeDelta delay =
 776       base::TimeDelta::FromMilliseconds(settings().scrollbar_fade_delay_ms);
 777   base::TimeDelta duration =
 778       base::TimeDelta::FromMilliseconds(settings().scrollbar_fade_duration_ms);
 779   switch (settings().scrollbar_animator) {
 780     case LayerTreeSettings::LinearFade: {
 781       return ScrollbarAnimationControllerLinearFade::Create(
 782                  scrolling_layer, layer_tree_host_impl_, delay, duration)
 783           .PassAs<ScrollbarAnimationController>();
 784     }
 785     case LayerTreeSettings::Thinning: {
 786       return ScrollbarAnimationControllerThinning::Create(
 787                  scrolling_layer, layer_tree_host_impl_, delay, duration)
 788           .PassAs<ScrollbarAnimationController>();
 789     }
 790     case LayerTreeSettings::NoAnimator:
 791       NOTREACHED();
 792       break;
 793   }
 794   return scoped_ptr<ScrollbarAnimationController>();
 795 }
 796
 797 void LayerTreeImpl::DidAnimateScrollOffset() {
 798   layer_tree_host_impl_->DidAnimateScrollOffset();
 799 }
 800
 801 bool LayerTreeImpl::use_gpu_rasterization() const {
 802   return layer_tree_host_impl_->use_gpu_rasterization();
 803 }
 804
 805 bool LayerTreeImpl::create_low_res_tiling() const {
 806   return layer_tree_host_impl_->create_low_res_tiling();
 807 }
 808
 809 void LayerTreeImpl::SetNeedsRedraw() {
 810   layer_tree_host_impl_->SetNeedsRedraw();
 811 }
 812
 813 const LayerTreeDebugState& LayerTreeImpl::debug_state() const {
 814   return layer_tree_host_impl_->debug_state();
 815 }
 816
 817 float LayerTreeImpl::device_scale_factor() const {
 818   return layer_tree_host_impl_->device_scale_factor();
 819 }
 820
 821 DebugRectHistory* LayerTreeImpl::debug_rect_history() const {
 822   return layer_tree_host_impl_->debug_rect_history();
 823 }
 824
 825 AnimationRegistrar* LayerTreeImpl::animationRegistrar() const {
 826   return layer_tree_host_impl_->animation_registrar();
 827 }
 828
 829 void LayerTreeImpl::AsValueInto(base::debug::TracedValue* state) const {
 830   TracedValue::MakeDictIntoImplicitSnapshot(state, "cc::LayerTreeImpl", this);
 831
 832   state->BeginDictionary("root_layer");
 833   root_layer_->AsValueInto(state);
 834   state->EndDictionary();
 835
 836   state->BeginArray("render_surface_layer_list");
 837   typedef LayerIterator<LayerImpl> LayerIteratorType;
 838   LayerIteratorType end = LayerIteratorType::End(&render_surface_layer_list_);
 839   for (LayerIteratorType it = LayerIteratorType::Begin(
 840            &render_surface_layer_list_); it != end; ++it) {
 841     if (!it.represents_itself())
 842       continue;
 843     TracedValue::AppendIDRef(*it, state);
 844   }
 845   state->EndArray();
 846 }
 847
 848 void LayerTreeImpl::SetRootLayerScrollOffsetDelegate(
 849     LayerScrollOffsetDelegate* root_layer_scroll_offset_delegate) {
 850   if (root_layer_scroll_offset_delegate_ == root_layer_scroll_offset_delegate)
 851     return;
 852
 853   if (!root_layer_scroll_offset_delegate) {
 854     // Make sure we remove the proxies from their layers before
 855     // releasing them.
 856     if (InnerViewportScrollLayer())
 857       InnerViewportScrollLayer()->SetScrollOffsetDelegate(NULL);
 858     if (OuterViewportScrollLayer())
 859       OuterViewportScrollLayer()->SetScrollOffsetDelegate(NULL);
 860     inner_viewport_scroll_delegate_proxy_.reset();
 861     outer_viewport_scroll_delegate_proxy_.reset();
 862   }
 863
 864   root_layer_scroll_offset_delegate_ = root_layer_scroll_offset_delegate;
 865
 866   if (root_layer_scroll_offset_delegate_) {
 867     root_layer_scroll_offset_delegate_->UpdateRootLayerState(
 868         TotalScrollOffset(),
 869         TotalMaxScrollOffset(),
 870         ScrollableSize(),
 871         total_page_scale_factor(),
 872         min_page_scale_factor(),
 873         max_page_scale_factor());
 874
 875     if (inner_viewport_scroll_layer_) {
 876       inner_viewport_scroll_delegate_proxy_ = make_scoped_ptr(
 877           new LayerScrollOffsetDelegateProxy(InnerViewportScrollLayer(),
 878                                              root_layer_scroll_offset_delegate_,
 879                                              this));
 880       inner_viewport_scroll_layer_->SetScrollOffsetDelegate(
 881           inner_viewport_scroll_delegate_proxy_.get());
 882     }
 883
 884     if (outer_viewport_scroll_layer_) {
 885       outer_viewport_scroll_delegate_proxy_ = make_scoped_ptr(
 886           new LayerScrollOffsetDelegateProxy(OuterViewportScrollLayer(),
 887                                              root_layer_scroll_offset_delegate_,
 888                                              this));
 889       outer_viewport_scroll_layer_->SetScrollOffsetDelegate(
 890           outer_viewport_scroll_delegate_proxy_.get());
 891     }
 892   }
 893 }
 894
 895 void LayerTreeImpl::UpdateScrollOffsetDelegate() {
 896   DCHECK(InnerViewportScrollLayer());
 897   DCHECK(root_layer_scroll_offset_delegate_);
 898
 899   gfx::Vector2dF offset =
 900       inner_viewport_scroll_delegate_proxy_->last_set_scroll_offset();
 901
 902   if (OuterViewportScrollLayer())
 903     offset += outer_viewport_scroll_delegate_proxy_->last_set_scroll_offset();
 904
 905   root_layer_scroll_offset_delegate_->UpdateRootLayerState(
 906       offset,
 907       TotalMaxScrollOffset(),
 908       ScrollableSize(),
 909       total_page_scale_factor(),
 910       min_page_scale_factor(),
 911       max_page_scale_factor());
 912 }
 913
 914 gfx::Vector2dF LayerTreeImpl::GetDelegatedScrollOffset(LayerImpl* layer) {
 915   DCHECK(root_layer_scroll_offset_delegate_);
 916   DCHECK(InnerViewportScrollLayer());
 917   if (layer == InnerViewportScrollLayer() && !OuterViewportScrollLayer())
 918     return root_layer_scroll_offset_delegate_->GetTotalScrollOffset();
 919
 920   // If we get here, we have both inner/outer viewports, and need to distribute
 921   // the scroll offset between them.
 922   DCHECK(inner_viewport_scroll_delegate_proxy_);
 923   DCHECK(outer_viewport_scroll_delegate_proxy_);
 924   gfx::Vector2dF inner_viewport_offset =
 925       inner_viewport_scroll_delegate_proxy_->last_set_scroll_offset();
 926   gfx::Vector2dF outer_viewport_offset =
 927       outer_viewport_scroll_delegate_proxy_->last_set_scroll_offset();
 928
 929   // It may be nothing has changed.
 930   gfx::Vector2dF delegate_offset =
 931       root_layer_scroll_offset_delegate_->GetTotalScrollOffset();
 932   if (inner_viewport_offset + outer_viewport_offset == delegate_offset) {
 933     if (layer == InnerViewportScrollLayer())
 934       return inner_viewport_offset;
 935     else
 936       return outer_viewport_offset;
 937   }
 938
 939   gfx::Vector2d max_outer_viewport_scroll_offset =
 940       OuterViewportScrollLayer()->MaxScrollOffset();
 941
 942   outer_viewport_offset = delegate_offset - inner_viewport_offset;
 943   outer_viewport_offset.SetToMin(max_outer_viewport_scroll_offset);
 944   outer_viewport_offset.SetToMax(gfx::Vector2d());
 945
 946   if (layer == OuterViewportScrollLayer())
 947     return outer_viewport_offset;
 948
 949   inner_viewport_offset = delegate_offset - outer_viewport_offset;
 950
 951   return inner_viewport_offset;
 952 }
 953
 954 void LayerTreeImpl::QueueSwapPromise(scoped_ptr<SwapPromise> swap_promise) {
 955   DCHECK(swap_promise);
 956   swap_promise_list_.push_back(swap_promise.Pass());
 957 }
 958
 959 void LayerTreeImpl::PassSwapPromises(
 960     ScopedPtrVector<SwapPromise>* new_swap_promise) {
 961   swap_promise_list_.insert_and_take(swap_promise_list_.end(),
 962                                      *new_swap_promise);
 963   new_swap_promise->clear();
 964 }
 965
 966 void LayerTreeImpl::FinishSwapPromises(CompositorFrameMetadata* metadata) {
 967   for (size_t i = 0; i < swap_promise_list_.size(); i++)
 968     swap_promise_list_[i]->DidSwap(metadata);
 969   swap_promise_list_.clear();
 970 }
 971
 972 void LayerTreeImpl::BreakSwapPromises(SwapPromise::DidNotSwapReason reason) {
 973   for (size_t i = 0; i < swap_promise_list_.size(); i++)
 974     swap_promise_list_[i]->DidNotSwap(reason);
 975   swap_promise_list_.clear();
 976 }
 977
 978 void LayerTreeImpl::DidModifyTilePriorities() {
 979   layer_tree_host_impl_->DidModifyTilePriorities();
 980 }
 981
 982 void LayerTreeImpl::set_ui_resource_request_queue(
 983     const UIResourceRequestQueue& queue) {
 984   ui_resource_request_queue_ = queue;
 985 }
 986
 987 ResourceProvider::ResourceId LayerTreeImpl::ResourceIdForUIResource(
 988     UIResourceId uid) const {
 989   return layer_tree_host_impl_->ResourceIdForUIResource(uid);
 990 }
 991
 992 bool LayerTreeImpl::IsUIResourceOpaque(UIResourceId uid) const {
 993   return layer_tree_host_impl_->IsUIResourceOpaque(uid);
 994 }
 995
 996 void LayerTreeImpl::ProcessUIResourceRequestQueue() {
 997   while (ui_resource_request_queue_.size() > 0) {
 998     UIResourceRequest req = ui_resource_request_queue_.front();
 999     ui_resource_request_queue_.pop_front();
1000
1001     switch (req.GetType()) {
1002       case UIResourceRequest::UIResourceCreate:
1003         layer_tree_host_impl_->CreateUIResource(req.GetId(), req.GetBitmap());
1004         break;
1005       case UIResourceRequest::UIResourceDelete:
1006         layer_tree_host_impl_->DeleteUIResource(req.GetId());
1007         break;
1008       case UIResourceRequest::UIResourceInvalidRequest:
1009         NOTREACHED();
1010         break;
1011     }
1012   }
1013
1014   // If all UI resource evictions were not recreated by processing this queue,
1015   // then another commit is required.
1016   if (layer_tree_host_impl_->EvictedUIResourcesExist())
1017     layer_tree_host_impl_->SetNeedsCommit();
1018 }
1019
1020 void LayerTreeImpl::AddLayerWithCopyOutputRequest(LayerImpl* layer) {
1021   // Only the active tree needs to know about layers with copy requests, as
1022   // they are aborted if not serviced during draw.
1023   DCHECK(IsActiveTree());
1024
1025   // DCHECK(std::find(layers_with_copy_output_request_.begin(),
1026   //                 layers_with_copy_output_request_.end(),
1027   //                 layer) == layers_with_copy_output_request_.end());
1028   // TODO(danakj): Remove this once crash is found crbug.com/309777
1029   for (size_t i = 0; i < layers_with_copy_output_request_.size(); ++i) {
1030     CHECK(layers_with_copy_output_request_[i] != layer)
1031         << i << " of " << layers_with_copy_output_request_.size();
1032   }
1033   layers_with_copy_output_request_.push_back(layer);
1034 }
1035
1036 void LayerTreeImpl::RemoveLayerWithCopyOutputRequest(LayerImpl* layer) {
1037   // Only the active tree needs to know about layers with copy requests, as
1038   // they are aborted if not serviced during draw.
1039   DCHECK(IsActiveTree());
1040
1041   std::vector<LayerImpl*>::iterator it = std::find(
1042       layers_with_copy_output_request_.begin(),
1043       layers_with_copy_output_request_.end(),
1044       layer);
1045   DCHECK(it != layers_with_copy_output_request_.end());
1046   layers_with_copy_output_request_.erase(it);
1047
1048   // TODO(danakj): Remove this once crash is found crbug.com/309777
1049   for (size_t i = 0; i < layers_with_copy_output_request_.size(); ++i) {
1050     CHECK(layers_with_copy_output_request_[i] != layer)
1051         << i << " of " << layers_with_copy_output_request_.size();
1052   }
1053 }
1054
1055 const std::vector<LayerImpl*>& LayerTreeImpl::LayersWithCopyOutputRequest()
1056     const {
1057   // Only the active tree needs to know about layers with copy requests, as
1058   // they are aborted if not serviced during draw.
1059   DCHECK(IsActiveTree());
1060
1061   return layers_with_copy_output_request_;
1062 }
1063
1064 void LayerTreeImpl::ReleaseResourcesRecursive(LayerImpl* current) {
1065   DCHECK(current);
1066   current->ReleaseResources();
1067   if (current->mask_layer())
1068     ReleaseResourcesRecursive(current->mask_layer());
1069   if (current->replica_layer())
1070     ReleaseResourcesRecursive(current->replica_layer());
1071   for (size_t i = 0; i < current->children().size(); ++i)
1072     ReleaseResourcesRecursive(current->children()[i]);
1073 }
1074
1075 template <typename LayerType>
1076 static inline bool LayerClipsSubtree(LayerType* layer) {
1077   return layer->masks_to_bounds() || layer->mask_layer();
1078 }
1079
1080 static bool PointHitsRect(
1081     const gfx::PointF& screen_space_point,
1082     const gfx::Transform& local_space_to_screen_space_transform,
1083     const gfx::RectF& local_space_rect,
1084     float* distance_to_camera) {
1085   // If the transform is not invertible, then assume that this point doesn't hit
1086   // this rect.
1087   gfx::Transform inverse_local_space_to_screen_space(
1088       gfx::Transform::kSkipInitialization);
1089   if (!local_space_to_screen_space_transform.GetInverse(
1090           &inverse_local_space_to_screen_space))
1091     return false;
1092
1093   // Transform the hit test point from screen space to the local space of the
1094   // given rect.
1095   bool clipped = false;
1096   gfx::Point3F planar_point = MathUtil::ProjectPoint3D(
1097       inverse_local_space_to_screen_space, screen_space_point, &clipped);
1098   gfx::PointF hit_test_point_in_local_space =
1099       gfx::PointF(planar_point.x(), planar_point.y());
1100
1101   // If ProjectPoint could not project to a valid value, then we assume that
1102   // this point doesn't hit this rect.
1103   if (clipped)
1104     return false;
1105
1106   if (!local_space_rect.Contains(hit_test_point_in_local_space))
1107     return false;
1108
1109   if (distance_to_camera) {
1110     // To compute the distance to the camera, we have to take the planar point
1111     // and pull it back to world space and compute the displacement along the
1112     // z-axis.
1113     gfx::Point3F planar_point_in_screen_space(planar_point);
1114     local_space_to_screen_space_transform.TransformPoint(
1115         &planar_point_in_screen_space);
1116     *distance_to_camera = planar_point_in_screen_space.z();
1117   }
1118
1119   return true;
1120 }
1121
1122 static bool PointHitsRegion(const gfx::PointF& screen_space_point,
1123                             const gfx::Transform& screen_space_transform,
1124                             const Region& layer_space_region,
1125                             float layer_content_scale_x,
1126                             float layer_content_scale_y) {
1127   // If the transform is not invertible, then assume that this point doesn't hit
1128   // this region.
1129   gfx::Transform inverse_screen_space_transform(
1130       gfx::Transform::kSkipInitialization);
1131   if (!screen_space_transform.GetInverse(&inverse_screen_space_transform))
1132     return false;
1133
1134   // Transform the hit test point from screen space to the local space of the
1135   // given region.
1136   bool clipped = false;
1137   gfx::PointF hit_test_point_in_content_space = MathUtil::ProjectPoint(
1138       inverse_screen_space_transform, screen_space_point, &clipped);
1139   gfx::PointF hit_test_point_in_layer_space =
1140       gfx::ScalePoint(hit_test_point_in_content_space,
1141                       1.f / layer_content_scale_x,
1142                       1.f / layer_content_scale_y);
1143
1144   // If ProjectPoint could not project to a valid value, then we assume that
1145   // this point doesn't hit this region.
1146   if (clipped)
1147     return false;
1148
1149   return layer_space_region.Contains(
1150       gfx::ToRoundedPoint(hit_test_point_in_layer_space));
1151 }
1152
1153 static const LayerImpl* GetNextClippingLayer(const LayerImpl* layer) {
1154   if (layer->scroll_parent())
1155     return layer->scroll_parent();
1156   if (layer->clip_parent())
1157     return layer->clip_parent();
1158   return layer->parent();
1159 }
1160
1161 static bool PointIsClippedBySurfaceOrClipRect(
1162     const gfx::PointF& screen_space_point,
1163     const LayerImpl* layer) {
1164   // Walk up the layer tree and hit-test any render_surfaces and any layer
1165   // clip rects that are active.
1166   for (; layer; layer = GetNextClippingLayer(layer)) {
1167     if (layer->render_surface() &&
1168         !PointHitsRect(screen_space_point,
1169                        layer->render_surface()->screen_space_transform(),
1170                        layer->render_surface()->content_rect(),
1171                        NULL))
1172       return true;
1173
1174     if (LayerClipsSubtree(layer) &&
1175         !PointHitsRect(screen_space_point,
1176                        layer->screen_space_transform(),
1177                        gfx::Rect(layer->content_bounds()),
1178                        NULL))
1179       return true;
1180   }
1181
1182   // If we have finished walking all ancestors without having already exited,
1183   // then the point is not clipped by any ancestors.
1184   return false;
1185 }
1186
1187 static bool PointHitsLayer(const LayerImpl* layer,
1188                            const gfx::PointF& screen_space_point,
1189                            float* distance_to_intersection) {
1190   gfx::RectF content_rect(layer->content_bounds());
1191   if (!PointHitsRect(screen_space_point,
1192                      layer->screen_space_transform(),
1193                      content_rect,
1194                      distance_to_intersection))
1195     return false;
1196
1197   // At this point, we think the point does hit the layer, but we need to walk
1198   // up the parents to ensure that the layer was not clipped in such a way
1199   // that the hit point actually should not hit the layer.
1200   if (PointIsClippedBySurfaceOrClipRect(screen_space_point, layer))
1201     return false;
1202
1203   // Skip the HUD layer.
1204   if (layer == layer->layer_tree_impl()->hud_layer())
1205     return false;
1206
1207   return true;
1208 }
1209
1210 struct FindClosestMatchingLayerDataForRecursion {
1211   FindClosestMatchingLayerDataForRecursion()
1212       : closest_match(NULL),
1213         closest_distance(-std::numeric_limits<float>::infinity()) {}
1214   LayerImpl* closest_match;
1215   // Note that the positive z-axis points towards the camera, so bigger means
1216   // closer in this case, counterintuitively.
1217   float closest_distance;
1218 };
1219
1220 template <typename Functor>
1221 static void FindClosestMatchingLayer(
1222     const gfx::PointF& screen_space_point,
1223     LayerImpl* layer,
1224     const Functor& func,
1225     FindClosestMatchingLayerDataForRecursion* data_for_recursion) {
1226   for (int i = layer->children().size() - 1; i >= 0; --i) {
1227     FindClosestMatchingLayer(
1228         screen_space_point, layer->children()[i], func, data_for_recursion);
1229   }
1230
1231   float distance_to_intersection = 0.f;
1232   if (func(layer) &&
1233       PointHitsLayer(layer, screen_space_point, &distance_to_intersection) &&
1234       ((!data_for_recursion->closest_match ||
1235         distance_to_intersection > data_for_recursion->closest_distance))) {
1236     data_for_recursion->closest_distance = distance_to_intersection;
1237     data_for_recursion->closest_match = layer;
1238   }
1239 }
1240
1241 static bool ScrollsAnyDrawnRenderSurfaceLayerListMember(LayerImpl* layer) {
1242   if (!layer->scrollable())
1243     return false;
1244   if (layer->IsDrawnRenderSurfaceLayerListMember())
1245     return true;
1246   if (!layer->scroll_children())
1247     return false;
1248   for (std::set<LayerImpl*>::const_iterator it =
1249            layer->scroll_children()->begin();
1250        it != layer->scroll_children()->end();
1251        ++it) {
1252     if ((*it)->IsDrawnRenderSurfaceLayerListMember())
1253       return true;
1254   }
1255   return false;
1256 }
1257
1258 struct FindScrollingLayerFunctor {
1259   bool operator()(LayerImpl* layer) const {
1260     return ScrollsAnyDrawnRenderSurfaceLayerListMember(layer);
1261   }
1262 };
1263
1264 LayerImpl* LayerTreeImpl::FindFirstScrollingLayerThatIsHitByPoint(
1265     const gfx::PointF& screen_space_point) {
1266   FindClosestMatchingLayerDataForRecursion data_for_recursion;
1267   FindClosestMatchingLayer(screen_space_point,
1268                            root_layer(),
1269                            FindScrollingLayerFunctor(),
1270                            &data_for_recursion);
1271   return data_for_recursion.closest_match;
1272 }
1273
1274 struct HitTestVisibleScrollableOrTouchableFunctor {
1275   bool operator()(LayerImpl* layer) const {
1276     return layer->IsDrawnRenderSurfaceLayerListMember() ||
1277            ScrollsAnyDrawnRenderSurfaceLayerListMember(layer) ||
1278            !layer->touch_event_handler_region().IsEmpty() ||
1279            layer->have_wheel_event_handlers();
1280   }
1281 };
1282
1283 LayerImpl* LayerTreeImpl::FindLayerThatIsHitByPoint(
1284     const gfx::PointF& screen_space_point) {
1285   if (!root_layer())
1286     return NULL;
1287   if (!UpdateDrawProperties())
1288     return NULL;
1289   FindClosestMatchingLayerDataForRecursion data_for_recursion;
1290   FindClosestMatchingLayer(screen_space_point,
1291                            root_layer(),
1292                            HitTestVisibleScrollableOrTouchableFunctor(),
1293                            &data_for_recursion);
1294   return data_for_recursion.closest_match;
1295 }
1296
1297 static bool LayerHasTouchEventHandlersAt(const gfx::PointF& screen_space_point,
1298                                          LayerImpl* layer_impl) {
1299   if (layer_impl->touch_event_handler_region().IsEmpty())
1300     return false;
1301
1302   if (!PointHitsRegion(screen_space_point,
1303                        layer_impl->screen_space_transform(),
1304                        layer_impl->touch_event_handler_region(),
1305                        layer_impl->contents_scale_x(),
1306                        layer_impl->contents_scale_y()))
1307     return false;
1308
1309   // At this point, we think the point does hit the touch event handler region
1310   // on the layer, but we need to walk up the parents to ensure that the layer
1311   // was not clipped in such a way that the hit point actually should not hit
1312   // the layer.
1313   if (PointIsClippedBySurfaceOrClipRect(screen_space_point, layer_impl))
1314     return false;
1315
1316   return true;
1317 }
1318
1319 struct FindTouchEventLayerFunctor {
1320   bool operator()(LayerImpl* layer) const {
1321     return LayerHasTouchEventHandlersAt(screen_space_point, layer);
1322   }
1323   const gfx::PointF screen_space_point;
1324 };
1325
1326 LayerImpl* LayerTreeImpl::FindLayerThatIsHitByPointInTouchHandlerRegion(
1327     const gfx::PointF& screen_space_point) {
1328   if (!root_layer())
1329     return NULL;
1330   if (!UpdateDrawProperties())
1331     return NULL;
1332   FindTouchEventLayerFunctor func = {screen_space_point};
1333   FindClosestMatchingLayerDataForRecursion data_for_recursion;
1334   FindClosestMatchingLayer(
1335       screen_space_point, root_layer(), func, &data_for_recursion);
1336   return data_for_recursion.closest_match;
1337 }
1338
1339 void LayerTreeImpl::RegisterSelection(const LayerSelectionBound& start,
1340                                       const LayerSelectionBound& end) {
1341   selection_start_ = start;
1342   selection_end_ = end;
1343 }
1344
1345 static ViewportSelectionBound ComputeViewportSelection(
1346     const LayerSelectionBound& bound,
1347     LayerImpl* layer,
1348     float device_scale_factor) {
1349   ViewportSelectionBound result;
1350   result.type = bound.type;
1351
1352   if (!layer || bound.type == SELECTION_BOUND_EMPTY)
1353     return result;
1354
1355   gfx::RectF layer_scaled_rect = gfx::ScaleRect(
1356       bound.layer_rect, layer->contents_scale_x(), layer->contents_scale_y());
1357   gfx::RectF screen_rect = MathUtil::ProjectClippedRect(
1358       layer->screen_space_transform(), layer_scaled_rect);
1359
1360   // The bottom left of the bound is used for visibility because 1) the bound
1361   // edge rect is one-dimensional (no width), and 2) the bottom is the logical
1362   // focal point for bound selection handles (this may change in the future).
1363   const gfx::PointF& visibility_point = screen_rect.bottom_left();
1364   float intersect_distance = 0.f;
1365   result.visible = PointHitsLayer(layer, visibility_point, &intersect_distance);
1366
1367   screen_rect.Scale(1.f / device_scale_factor);
1368   result.viewport_rect = screen_rect;
1369
1370   return result;
1371 }
1372
1373 void LayerTreeImpl::GetViewportSelection(ViewportSelectionBound* start,
1374                                          ViewportSelectionBound* end) {
1375   DCHECK(start);
1376   DCHECK(end);
1377
1378   *start = ComputeViewportSelection(
1379       selection_start_,
1380       selection_start_.layer_id ? LayerById(selection_start_.layer_id) : NULL,
1381       device_scale_factor());
1382   if (start->type == SELECTION_BOUND_CENTER ||
1383       start->type == SELECTION_BOUND_EMPTY) {
1384     *end = *start;
1385   } else {
1386     *end = ComputeViewportSelection(
1387         selection_end_,
1388         selection_end_.layer_id ? LayerById(selection_end_.layer_id) : NULL,
1389         device_scale_factor());
1390   }
1391 }
1392
1393 void LayerTreeImpl::RegisterPictureLayerImpl(PictureLayerImpl* layer) {
1394   layer_tree_host_impl_->RegisterPictureLayerImpl(layer);
1395 }
1396
1397 void LayerTreeImpl::UnregisterPictureLayerImpl(PictureLayerImpl* layer) {
1398   layer_tree_host_impl_->UnregisterPictureLayerImpl(layer);
1399 }
1400
1401 void LayerTreeImpl::InputScrollAnimationFinished() {
1402   layer_tree_host_impl_->ScrollEnd();
1403 }
1404
1405 }  // namespace cc